The spiteful biography is hardly an unusual thing, but this Anthony
Burgess bio seems like an extreme member of the genre:

Some of his observations about Burgess's touchiness and
verbosity are spot on. But the longer the book proceeds, the more
preposterous the claims become: Burgess "simply wasn't very bright",
"he hated being a human being". At least twice Lewis wishes Burgess
dead, as if his actual death, in 1993 (described as him "conking
out"), wasn't enough. Elsewhere, having rubbished his subject's powers
of invention, he tries to impress us with his own, transcribing an
imaginary dialogue from the 1960s that's unfunny and name-dropping in
the extreme.

...

As to the footnotes, they're largely an excuse to pick off enemies -
not only Burgess and his widow Liana ("that frightful woman... an
obscure Italian translator"), but Stanley Kubrick ("piss-poor"), Clive
James ("a professional nincompoop... a prat"), Martin Amis ("a writer
with nothing to say"), and many more.